The present invention relates to a disk diaphragm for a loudspeaker having an intermediate layer between the disklike radiating layer and the voice coil.
Such a diaphragm is known from German Offenlegunschrifft DE-OS No. 29 33 425.
A loudspeaker diaphragm must meet two very important requirements: it must be light in order to be able to follow steep signal edges without delay, and it must be stiff in order to follow the signal steadily throughout its area and without being deformed.
If the first requirement is not met, the loudspeaker has a poor response to pulses and high audio frequencies. If the second requirement is not met, the electric signals are not converted into precisely corresponding, piston-like movements of the diaphragm, but instead the latter is deformed by partial oscillations. Such deformations cause sound pressure waves which do not correspond to the electric drive signal, i.e., which reproduce the latter in distorted form. Furthermore, partial oscillation causes considerable additional stress in the diaphragm material, and can result in fatigue, and even destruction, of the diaphragm.
In order to avoid these disadvantages, it has become common practice to replace the well known and widely used conical paper diaphragm by a disk diaphragm, because the latter's radiation centers lie in one plane.
The known disk diaphragm consists of an essentially truncated-cone-shaped molded part of foamed polystyrene on whose flat front side two films are disposed one on top of the other as a disklike radiating layer.
Such a structure is rather complicated and, therefore, expensive to manufacture.